A panel of vaccine advisers at the Food and Drug Administration will meet Friday to discuss whether the agency should grant emergency use authorization to the COVID-19 vaccine developed by Johnson & Johnson-owned Janssen Pharmaceuticals. Here are the answers to the most pressing questions.
How efficacious is the vaccine?
The FDA’s panel of vaccine experts reported Wednesday that the vaccine was 66% effective overall in preventing moderate and severe COVID-19 cases. The vaccine was also demonstrated to by roughly 85% effective overall at preventing hospitalization and 100% effective at preventing death in all three regions where the shot was tested.
In the United States, the efficacy rate was 72%, 61% in Latin America, and 64% in South Africa. Researchers attributed the disparate rates to the different coronavirus variants circulating across each region.
Results of the 44,000-person clinical trials showed consistent protection across all variants and regions, “including South Africa where nearly all cases of COVID-19 (95%) were due to infection” with a highly contagious variant of the coronavirus.
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What differentiates it from the Moderna and Pfizer vaccines?
Just one shot of the Johnson & Johnson vaccine provides its full level of protection, whereas the Moderna and Pfizer vaccines require two shots spaced 28 and 21 days apart, respectively. The addition of a single-dose vaccine would be a boon to the Biden administration’s efforts to accelerate immunizations.
The shot also differs in how it works to prevent infection with the other two vaccines. Pfizer’s and Moderna’s shots use synthesized mRNA to carry instructions for replicating spike proteins on the coronavirus to cells. That way, if the body is infected, the immune system will know exactly how to fight the coronavirus.
Johnson & Johnson, however, created an adenovirus-vectored vaccine. The shot uses a harmless virus to act as a Trojan horse that introduces the genetic material necessary to teach cells how to attack the coronavirus. Adenovirus-vectored vaccines are not new. Johnson & Johnson’s vaccine to prevent Ebola the same technology was approved for use in the European Union last summer. Researchers have also explored the possibility of using the technology to develop a vaccine for the prevention of HIV.
The vaccine can also be stored in temperatures of 36 degrees to 46 degrees Fahrenheit for up to three months, making it most appealing for facilities that lack the ultracold freezers necessary to keep Pfizer’s two-dose vaccines viable for up to six months.
What kinds of adverse effects did the trial participants experience?
The FDA report’s authors also concluded that the shot has a “favorable safety profile with no specific safety concerns identified that would preclude issuance of an [emergency use authorization].” In fact, the adverse effects most commonly associated with the shot (pain at the injection site, headache, fatigue, and muscle pain) look very similar to those reported for the Pfizer and Moderna vaccines. These kinds of reactions indicate that the vaccine has successfully prompted an immune system response.
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How many doses of the shot will be added to the national supply?
Johnson & Johnson says it is on track to ship 100 million shots by the end of June, fulfilling the order placed by the federal government last summer for $1 billion. The company expects to ship out enough shots to immunize 20 million people by the end of March.
The company has already fallen behind schedule for distribution, however. Johnson & Johnson will be able to ship about 4 million doses immediately upon receiving the emergency use authorization, according to Dr. Richard Nettles, the vice president of medical affairs at the pharmaceutical subsidiary Janssen.
White House COVID-19 response coordinator Jeff Zients said Wednesday that the federal government is “ready to roll out this vaccine without delay.”
Is it already in use somewhere else?
The vaccine has not been authorized for use anywhere. However, Johnson & Johnson has struck a deal with the EU to supply 200 million doses to member states once authorized. The decision to authorize the shot will come from EU regulators in mid-March, Reuters reported.
The South African government decided earlier this month that it would abandon plans to distribute the Oxford-AstraZeneca vaccine and instead utilize Johnson & Johnson’s vaccine, which is still in testing. A small study of the Oxford-AstraZeneca shot, originally expected to be the most promising candidate for developing countries as it’s cheaper and easier to transport, suggested that it offers very minimal protections against the dominant strain there.
